This invention relates generally to optical fibers, optical devices, electronic devices and optoelectronic devices, and in particular relates to fiber materials selection, fiber structure design, and fiber drawing techniques for producing a fiber with desired functionality.
A combination of conducting, semiconducting, and insulating materials in well-defined geometries, prescribed micro- and nano-scale dimensions, and with intimate interfaces is essential for the realization of virtually all modern electronic and optoelectronic devices. Historically, such devices are fabricated using a variety of elaborate microfabrication technologies that employ wafer-based processing. The many wafer-based processing techniques currently available enable the combination of certain conducting, semiconducting, and insulating materials in small feature sizes and high device packing densities. But in general, microfabrication techniques are restricted to planar geometries and planar conformality and limited device extent and/or materials coverage area. Microfabricated devices and systems also in general require packaging and typically necessitate very large capital expenditures.
Conversely, modern preform-based optical fiber production techniques can yield extended lengths of material and enable well-controlled geometries and transport characteristics over such extended lengths. In further contrast to wafer-based processing, fiber preform drawing techniques are in general less costly and less complicated. But in general, preform-based optical fiber production has been restricted to large fiber feature dimensions and a relatively small class of dielectric materials developed primarily for enabling optical transmission. A wide range of applications therefore remain to be addressed due to the limitations of both conventional fiber preform-based drawing technologies and conventional microfabrication technologies.
One example of such an application is thermal sensing and thermography. Thermal sensing and thermography can yield important information about the dynamics of many physical, chemical, and biological phenomena. Spatially-resolved thermal sensing can enable failure detection in technological systems where the failure mechanism can be correlated with localized changes in temperature. Indeed, infrared imaging systems have become ubiquitous for applications where line-of-sight contact can be made between an object to be measured and a measuring camera lens.
But many critical applications do not lend themselves to radiative infrared imaging due to the subterraneous nature of the monitored surface, spatial constraints, or cost considerations. The challenge of monitoring the skin temperature beneath the thermal tiles on the space shuttle represents a good example in which high-spatial-resolution information is required on very large surface areas and where the monitoring cannot be performed using traditional thermal imaging systems. The problem of continuously monitoring and detecting a thermal excitation on very large areas (100 m2) with high resolution (1 cm2) is one that has remained largely unsolved, not being well-addressed by conventional microfabricated systems or conventional fiber-based systems.